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Rickheatdoc :

If your burner ignites then goes out a few seconds later then you may have a flame sensor issue. The flame sensor can be cleaned off (very carefully) with fine sand paper. There may also be some rust flakes that are grounding the sensor out

Customer :

I cleaned the sensor and wiped it off with a clean cloth. Currently the burner has stopped igniting, yesterday.

Customer :

do I have to click "accept"? what does clicking accept mean?

Rickheatdoc :

It means you are satisfied with my answer and I am compensated for my time. If you have follow up questions you can still ask them even after accepting

Rickheatdoc :

You should unplug the the heater wait a couple minutes then plug it back in. This will reset the heater. If it doesn't work I need to know when it fails

Rickheatdoc :

just wiping off the flame sensor probably won't do much

Customer :

ok, I understand. Sorry, I was heating water, then in the basement, again. Unplugged after cleaning sensor. It appears to have remained in the same place. Vacuumed out the brittle pieces from the grating above the burner. Before that, in you didn't see, I made sure the hoses weren't leaking, verified the blower sensor opened and closed. No debris in exhaust piping, piped out to driveway. Plug in, blower comes on, glow rod comes on, no flame now, then goes out. Does this 3 times. Is there a sensor that is interchageable? or if bad, need the exact one?

Rickheatdoc :

back in a minute

Customer :

It would flame during the series last week keeping it like room temp, but now won't flame. Trouble shooting light series is saying low gas, (been here 2 yrs myself and it's 6 yrs old) or electricity polarity issue. Like I said, it's worked fine for 2 yrs

Rickheatdoc :

what do the indicator lights on the gas valve show (how many, which ones)?

Customer :

The green one on the left skip 2 then the 4th and 5th last one not lit. I looked up the light code. Besides polarity, gas flow, it also says may not be positioned correctly, but it's worked fine for a long time.

Rickheatdoc :

If the hsi ignitor hasn't been replaced then it's not likely it's positioned incorrectly. I can give you something to try but I am a bit concerned about having anyone except a plumber try this

Rickheatdoc :

do you want to give it a shot?

Customer :

If I have to call someone, it will only be the third time in life, and I'm 51. Dad taught how to do. I won't do crazy things and work in safety, so tell me what it is and I'll see if I feel comfortable doing the check.

Rickheatdoc :

Ok, for some reason your main burner is not igniting. Your unit performs all the steps up to the point of ignition then fails. The error code is no help. So, what I propose is this; restart the unit with the burner access doors off. Once the hsi glows hold a match to the burner and see if there is indeed any gas there or if the gas valve isn't opening when it should. I have a telescoping tool with an alligator clip on the end that I would use for this purpose. This would allow me to put a match in the clip and reach into the chamber without sticking my fingers in there.

Rickheatdoc :

if the main burner won't light because there is no gas, then you either have a faulty gas valve or your ignitor isn't telling the gas valve it is glowing

Customer :

Gotcha, simple enough, but, does it matter that through all the steps, many times cycled, that I don't smell any gas?

Rickheatdoc :

it could be an indication that the gas valve isn't opening but relying on smell is not very accurate. A match will tell you for sure

Customer :

put a wooden match on an extention, turned the power off, waited, turned it on, during first two cycles put the match at the tip of orafice and it wouldn't light. I'll admit, the heart sped up for a sec ha

Rickheatdoc :

I wouldn't have even suggested it if I thought there was a chance of a calamity but gas does have a way of increasing the heart rate.

Rickheatdoc :

So my 2 previously mentioned culprits and now suspect

Customer :

So, if I go shopping, am I looking for the exact flame sensor for this model? that's probably the cheaper of the two. If asking for the part, or on line if I have to, is the gas valve an expensive part? I know the thermostat is and some of the others are. Today, it's a bird bath unless I run to my sons .

Rickheatdoc :

This unit might (barely) be under warranty. I'd go to the AO Smith sight and use their warranty check page to find out. I don't think the HSI will be covered (it might) more likely the gas valve will be. The gas control valve is pretty pricey (~$200)

Customer :

One more question before I accept and thank you for teaching me some things and narrowing my issue down to probably one of the 2. Can I find the HSI at home depot or some place I can drive to in Columbus Ohio? I'm in Delaware and know there won't be anywhere up here.

Customer :

If possible, I should prob take it with me for length and coupler comparing

Rickheatdoc :

Highly unlikely, HD or lowes don't carry AO Smith (at least not around here) and these parts are too technical for general retail. A plumbing supply house that sells AO Smith is your only shot

Customer :

We do have Worly's commercial plumbing in Delaware. Thanks so much and Go Steelers, sorry. had to

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